When completed, his home is expected to be the most sustainable built in an Australian urban area, and his letterbox almost a bill-free zone.

From his street in Tighes Hill, a Newcastle suburb, the house will look like a modern home in the midst of a working-class suburb. The first hint of something unusual will be the wind turbine on the roof and the absence of lawn. The most important innovations will be almost invisible.

Underneath his house, and designed to be part of the foundation, will be a 40,000-litre rainwater storage tank which will supply all of the water needs for Mr Hockings, his partner and 13-year-old son. The house will not be connected to the mains water supply.

Mr Hockings, a professional builder and environmental consultant to the Master Builders Association, is installing water-free composting toilets, which will save tens of thousands of litres every year. Grey water from washing machines, showers and other household uses will be diverted to a series of natural sand filters and ponds and then reused on a small orchard.

"Instead of treating it as a waste, we treat it as a resource and apply the water and nutrients to avocados, mangoes, macadamias, custard apples figs and citrus," he said.

After good design, the biggest savings come from installing devices like water-efficient shower roses and appliances like front-loading washing machines. By keeping lawns to an absolute minimum, and by planting hardy, drought-resistant native grasses, further water savings can be made. His landscaping includes well-mulched native trees and ground covers as well as permeable paving.

"The simplest thing people can do is make their houses smaller and built to last longer. We are building this house to last for at least 100 years if not 200, achieving maximum use from minimum resources," Mr Hockings said.

The new house is on a 300-square-metre block and is adjacent to their 1920s home.

"This will be a three-bedroom home with a garage, and it's less than 150 square metres. The $20,000 or $30,000 being spent on novel environmental construction is roughly equivalent to reducing 20 or 30 square metres of floor area, and we'll never have water or energy bills," he said. Mr Hocking plans to generate power from a wind turbine, solar panels and a small biodiesel generator.

Saving water also saves energy. "Our on-site water supply and waste-water treatment systems use far less energy than the utilities would use to pump water and waste through kilometres of piping."

An architect and senior research consultant at the Institute for Sustainable Futures at the University of Technology, Sydney, Caitlin McGee, said the Hockings's progress was "as far towards sustainable as anybody's gone in a house".